Since the introduction of prostate specific antigen (PSA) testing in the late 1980's, the number of new cases of localized prostate cancer has risen dramatically. Controversy surrounds the treatment of this disease because no randomized trials clearly document the benefit of aggressive treatment versus conservative management. Our research goal is to obtain more accurate estimates of the treatment efficacy of radical surgery and radiation therapy by determining the need for secondary cancer therapy and the length of patient survival stratified by key variables known to impact survival. Using the Connecticut Tumor Registry (CTR) as a case finding tool, we propose to assemble a population-based cohort of over 4000 men diagnosed with localized prostate cancer during the period 1990-1992 and follow them prospectively to achieve the following specific aims: For men who received either radical surgery, radiation therapy or no immediate therapy as their primary therapy, we will (1) Determine the frequency and timing of secondary cancer therapies among men treated in community practices, (2) Determine the frequency and timing of serum PSA elevation among men treated in community practices, (3) Determine the ten year cause-specific and all-cause survival outcomes for men treated in community practices. All results will be stratified according to the following variables that are known to impact progression and survival: patient age, race, co-morbidities, diagnostic biopsy tumor histology estimated by the Gleason score, and tumor volume estimated by pre-biopsy PSA level. Using data collected from this cohort of patients, we will address the following questions: (1) How to do men undergoing radical surgery, radiation therapy or no immediate treatment differ according to age, race, comorbidities, diagnostic biopsy histology or pre-treatment PSA? (2) What is the relative risk of receiving secondary cancer therapy within ten years of initial treatment for men undergoing radical surgery, radiation therapy or no immediate treatment after controlling for patient age, race, co-morbidities, diagnostic biopsy histology or pre-treatment PSA? and (3) What is the relative ability of patient age, race, co-morbidities, diagnostic biopsy histology or pre-treatment PSA to predict disease progression, cause specific and all-cause survival? Since the CTR continually monitors the vital status of patients included in the registry, information available from this study will eventually permit 15 and 20 year all-cause and cause-specific survival analyses for the entire cohort.